The Rhinos were thrashed 46-16 in France at the weekend, but McDermott has pointed towards the second-half tries scored by Ryan Hall, Danny Maguire and Joel Moon as evidence that his side did not "roll over".
"What I didn't see was a group of blokes who don't care or who turned it in. I thought we again had a real crack," McDermott told the Yorkshire Post.
"Clearly it wasn't good enough and some things weren't right, but there's no lack of effort there.
"Every time we play I am really proud of them and I was really proud of the way we didn't roll over. It could have been a 50 or 60 scoreline, but we wouldn't let it be."
Leeds take on the Castleford Tigers on Thursday evening in their next Super League Super 8s fixture.